1. Field of the Invention
The present invention relates to a device for dispensing, by means of a manually operable pump, fluid substances contained under airtight conditions in a deformable bag housed in a rigid container, and more particularly a device in which the bag has a mouth with a flange which extends beyond the neck of the container in which the bag is inserted, the pump having a ring cap for its removable mounting on the container neck and being provided with elements which couple to the bag flange to cause the bag to be extracted from the container when the pump is uncoupled and removed from the container when all the substance initially introduced into the bag has been dispensed.
2. Description of the Related Art
It is known to enclose fluid substances (both liquid and creamy) in containers from which these substances are dispensed by manually operating a small pump mounted on the mouth of a respective container. Pump operation causes a quantity of fluid substance to be withdrawn from the container in which—if the container is rigid—a vacuum forms which would prevent further substance withdrawal and dispensing if air were not allowed to enter the container (which generally takes place in those regions in which the pump makes contact with and slides on the pump body), or if the container did not comprise a base sealedly movable along an internal cylindrical surface of the container (see for example U.S. Pat. No. 4,691,847, U.S. Pat. No. 4,694,977 and U.S. Pat. No. 5,971,224): this latter system for compensating the container internal volume by reducing its internal volume while maintaining the internal pressure constant is however very laborious and costly.
In many cases it is opportune or necessary that the fluid substance to be dispensed by a pump never comes into contact with the atmosphere inside the container (with the dispensing pump mounted on it): sealing the fluid out of contact with the atmosphere is important if the composition of the fluid within the container is not to undergo alteration, or if it is essential that the fluid substance enclosed in the container remains sterile. To achieve this, U.S. Pat. No. 3,420,413 proposes a device comprising a bag containing a fluid substance which has to remain isolated from the atmosphere within the bag which (see column 4, lines 22-28) is made of an elastically deformable flexible material and has a neck on which a support element (having a profiled aperture for housing a pump) is sealedly applied after the bag has been filled with the fluid substance to be dispensed: after this, a pump is sealedly mounted on said support element to hence prevent contamination of the fluid substance by the air (column 5, lines 15-38). The bag containing the fluid substance and having the pump sealedly mounted on its neck is then inserted into a rigid container (obviously being very careful that the free end of the rigid container does not come into contact with the bag filled with fluid substance, in order not to break it) on which said support element is then positioned and fixed (column 5, lines 56-61). Hence between the outer surface of the bag and the inner surface of the rigid container an interspace is formed which is connected to atmosphere via a hole provided in the container base; in this manner, when the fluid substance is withdrawn from the bag by operating the pump, the bag is squeezed by the atmospheric pressure so that it can be easily withdrawn and expelled to the outside by the pump (column 5, lines 70-73). The main drawback of the aforesaid device is that the deformable bag must be filled with fluid substance before the bag is inserted into the respective rigid container and that the operation involved in inserting the bag into the container is very delicate because the bag can be easily torn while being inserted into the container interior.
JP 05 031790A and JP 05 031791A published on Sep. 2, 1993 describe how a bag of elastically deformable material can be produced directly within a rigid container. For this purpose an elongated preform (made of thermoplastic material and having an elongated hollow cylindrical body, open at one end where the preform presents a neck from which a flange radially projects) is inserted into a rigid container having a mouth from which a neck extends, on the free edge of which there rests the flange of the preform, which is heated and then inflated within the container, until a bag forms, the outer surface of which adheres (at least for a large part of its surface) to the inner surface of the container. The bag obtained in this manner also has a neck, at least an end portion of which presents outwardly projecting longitudinal ribs, with some radial ribs or projections projecting from that surface of the preform flange which faces the free edge of the neck of the container in which the bag is inserted: these ribs or projections define passages for the air which penetrates from the outside between the container and bag to enable this latter to flatten or inwardly deform during outward dispensing of the fluid substance through the pump, so preventing the formation inside the bag of a vacuum which would prevent dispensing of the fluid substance.
US 2004/0112921A1 published on Jun. 17, 2004 (in the name of the same applicant as the two aforestated Japanese patent applications) illustrates a device comprising a container and a deformable bag such as that of the two Japanese patent applications, and in which a manually operable pump is mounted by means of a ring cap having a thread which engages and screws onto a corresponding screw thread projecting from the surface of the container neck. The pump is maintained pressed by the ring cap (screwed onto the container neck) to seal against the flange projecting from the bag mouth, passages being provided enabling air to pass from the outside to the space between the bag and container to enable the bag to gradually shrink onto itself as the quantity of fluid substance dispensed by the pump increases. Devices totally similar (and hence not requiring further comment) to that of US2004/011292A1 are described in DE 770773 U1 and NL 1 021 710 C2.
In all these devices, when (on termination of fluid substance dispensing from the respective deformable bags) the ring cap retaining the pump on the neck of the deformable bag is unscrewed from the spiral rib of the neck of the respective container and the pump is removed, the deformable bag remains retained inside the container. This constitutes a problem because national laws regarding environmental protection require the deformable bag (made of thermoplastic material or the like) to be disposed of separately from the container (which can be of glass or other rigid material suitable for the purpose). In the known devices described in the aforestated prior patents, it is not however possible to easily extract the deformable bag from the containers, when fluid substance dispensing has terminated.